#include <cctype> #include <iostream> using namespace std; string encode(string str) { string res = str; for (int i = 0; i < str.length(); ++i) { if (isalpha(str[i]) && isupper(str[i])) { res[i] = 'a' + (((res[i] - 'A') + 1) % 26); } else if (isalp...